The field of the invention is systems and methods for magnetic resonance imaging (“MRI”) and magnetic resonance spectroscopy (“MRS”). More particularly, the invention relates to systems and methods for assessing the effects of repetitive head injuries with MRS and magnetic resonance spectroscopic imaging (“MRSI”).
Recent studies have demonstrated that changes in cerebral metabolites and other biochemicals after severe traumatic brain injury may correlate strongly with clinical grade and patient outcome. Most of these studies showed the following changes in both gray matter and white matter regions in patients with severe traumatic brain injury when compared to age-matched controls: a persistent reduction of N-acetyl aspartate (“NAA”), presence of lipid and lactate, and elevated concentrations of cerebral osmolytes, including choline and myo-inositol. For example, in a previous study by B. D. Ross, et al., titled “1H MRS in Acute Traumatic Brain Injury,” J. Magn. Reson. Imaging, 1998; 8(4):829-840, it was shown that there are changes in cerebral metabolites after acute traumatic brain injury, and a strong correlation with clinical grade and patient outcome. This study showed that patients with traumatic brain injury, when compared to age-matched controls, exhibited a persistent reduction of NAA, a putative neuronal marker that indicates neuronal and axonal injury; presence of lipid and lactate, which are MRS markers of hypoxia; and elevated concentrations of cerebral osmolytes, including choline and myo-inositol, in both gray matter and white matter regions of the brain. This study was, however, limited to employing one-dimensional MRS techniques, which are incapable of measuring subtler changes in cerebral metabolites.
Sports-related brain injuries are milder, and potentially different types of head injuries altogether than severe, or even mild, traumatic brain injuries, making it more difficult to identify subtle changes in biochemical concentrations following such repetitive head injuries. Recent studies have shown that one of the long term effects of repetitive head injury is the neurodegenerative disease referred to as chronic traumatic encephalopathy (“CTE”). CTE is characterized, post mortem, by abnormal tau accumulation in the brain. However, there is currently no known technique for identifying early hallmarks of CTE and whether a patient subjected to repetitive head injuries is at risk for developing CTE.
In light of the foregoing, it would therefore be desirable to provide a method for non-invasively testing, in vivo, patients with repetitive head injury, such as athletes and soldiers, during the lifetime of the patient for diseases related to the repetitive head injury.